Treating cardiovascular diseases by catheter intervention is a conventional therapy at the present, and it specifically means that various materials, devices and the like are put into parts such as the heart, an artery blood vessel and a vein of a human body via a catheter intervention therapy to treat the cardiovascular diseases.
For example, an interventional medical instrument, such as an Atrial Septal Defect (ASD) occluder, a Ventricular Septal Defect (VSD) occluder, a Patent Ductus Arteriosus (PDA) occluder and a Patent Foramen Ovale (PFO) occluder, is placed via the catheter intervention method, and then reaches a defective part of the heart so as to occlude the defect to treat congenital heart diseases. For another example, an occluder may be put into a left atrial appendage through a catheter intervention method to prevent a left atrial appendage thrombus caused by atrial fibrillation and avoid apoplexy caused by a fact that the thrombus goes up to a brain, or prevent systematic embolization caused by a fact that the thrombus reaches other portions of a body through a blood circulation system of a human body. Or for another example, a lung volume reduction device is delivered to a diseased position of a bronchus of the lung to treat pulmonary emphysema.
During delivery of the interventional medical device into the heart, the artery blood vessel, the vein, the left atrial appendage and the bronchus of the lung through a delivery system, the interventional medical device is generally pushed to a predetermined part through a flexible pushing steel cable, and then connection between the interventional medical device and the pushing steel cable is cut off to release the interventional medical device; and whether the release position of the interventional medical device is appropriate or not, whether the interventional medical device is poorly spread or not, and whether an operation effect is satisfactory or not are confirmed through radiography or ultrasonic.
In an actual use process, to reduce trauma of patients, it should reduce inner and outer diameters of a delivery sheath as much as possible. However, under a condition that the model of the selected interventional medical device is not changed, the inner diameter of the sheath used cooperatively is smaller, and the pushing resistance of the interventional medical device is greater; and particularly when a path of pushing the interventional medical device is relatively long, a supporting force of the flexible steel cable will be insufficient, which directly leads to a fact that it is relatively easy for the interventional medical device to deviate from a predetermined position, thus prolonging the operation time and increasing the operation risk of the patients.